Danica McKellar ("Winnie Cooper" from the 80s hit TV series The Wonder Years) is living proof that brain and beauty can go hand in hand: she has written a textbook to encourage middle school girls to learn math.

This has inspired Jason from our pal mental_floss blog to compile a list of twenty celebrities that actually have brains in addition to mere good looks.

For example, consider Mayam Bialik (from Blossom):

We don’t set the bar too high for child stars. Avoid jail and rehab and exceed all expectations. But Mayim Bialik has kept her name out of the tabloids and her nose in the books. The former Blossom star is closing in on her PhD in neuroscience at UCLA. She’s writing her thesis on Prader-Willi syndrome, a strange DNA disorder that forces its victims to go crazy and destroy their homes in a desperate search for food.